Various systems and applications apply image adaptation and compression techniques to reduce the data size of digitally-represented images. A number of compressed image standards are known in the art, such as the Graphic Interchange Format (GIF) standard, the Portable Network Graphics (PNG) standard and the Joint Photographic Experts Group (JPEG) standard.
The GIF file format is described in a specification published by Compuserve Inc. (Columbus, Ohio) entitled “Graphics Interchange Format Programming Reference,” July 1990, which is incorporated herein by reference. The specification is available at www.w3.org/Graphics/GIF/spec-gif89a.txt.
The PNG file format is specified in a recommendation of the World Wide Web Consortium (W3C) entitled “Portable Network Graphics (PNG) Specification (Second Edition) Information technology—Computer Graphics and Image Processing—Portable Network Graphics (PNG): Functional Specification,” November 2003, which is incorporated herein by reference. The PNG specification is also available at www.w3.org/TR/PNG.
The JPEG file format is defined in recommendation T.81 of the International Telecommunication Union (ITU) entitled “Information Technology—Digital Compression and Coding of Continuous-Tone Still Images—Requirements and Guidelines,” September 1992, which is incorporated herein by reference. Further information regarding the JPEG standard is also available at www.jpeg.org.